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The Radar iOS SDK can leverage the device’s motion sensors and CoreMotion framework to improve location tracking accuracy and reduce battery usage by detecting when the user is stationary, walking, driving, or performing other activities.

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Overview

Motion detection enables:
  • Stop detection: Identify when a user has stopped moving
  • Activity classification: Determine if the user is stationary, walking, running, biking, or driving
  • Floor level detection: Detect changes in altitude for indoor positioning
  • Battery optimization: Reduce location updates when the device is stationary

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Enable motion detection

To enable motion detection, set the useMotion property on your tracking options: 
import RadarSDK

let trackingOptions = RadarTrackingOptions()
trackingOptions.useMotion = true

Radar.startTracking(trackingOptions: trackingOptions)
Motion detection requires the RadarSDKMotion framework to be integrated separately. The SDK will automatically detect its presence and enable motion features.

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Request motion permissions

Motion & Fitness permissions are required to access activity data:
1

Add Info.plist entry

Add the motion usage description to your Info.plist:
<key>NSMotionUsageDescription</key>
<string>We use motion data to improve location accuracy and optimize battery usage.</string>
2

Request permission programmatically

The SDK automatically requests motion permissions when you enable motion tracking. You can also manually request permissions:
import CoreMotion

let motionManager = CMMotionActivityManager()
motionManager.startActivityUpdates(to: .main) { activity in
    // Permission granted
    motionManager.stopActivityUpdates()
}

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Activity types

The SDK can detect the following activity types:
ActivityDescription
RadarActivityTypeStationaryDevice is stationary
RadarActivityTypeFootUser is walking
RadarActivityTypeRunUser is running
RadarActivityTypeBikeUser is biking
RadarActivityTypeCarUser is driving
RadarActivityTypeUnknownActivity cannot be determined

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Stop detection

Configure stop detection parameters to determine when a user has stopped moving: 
let trackingOptions = RadarTrackingOptions()

// Stop detection configuration
trackingOptions.stopDuration = 140 // seconds
trackingOptions.stopDistance = 70 // meters
trackingOptions.useMotion = true

Radar.startTracking(trackingOptions: trackingOptions)
The device is considered stopped when it stays within the stopDistance for at least stopDuration.

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Optimize battery with stop detection

Reduce battery usage by stopping location updates when the device is stationary: 
let trackingOptions = RadarTrackingOptions()
trackingOptions.desiredStoppedUpdateInterval = 0 // Shut down when stopped
trackingOptions.desiredMovingUpdateInterval = 150 // Update every 2.5 min when moving
trackingOptions.stopDuration = 140
trackingOptions.stopDistance = 70
trackingOptions.useMotion = true

Radar.startTracking(trackingOptions: trackingOptions)

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Pressure sensor integration

Enable pressure sensor data to detect floor level changes: 
let trackingOptions = RadarTrackingOptions()
trackingOptions.usePressure = true
trackingOptions.useMotion = true

Radar.startTracking(trackingOptions: trackingOptions)
Pressure sensor data is available on devices with a barometer. The SDK uses both relative altitude (pressure-based) and absolute altitude (iOS 15+) when available.

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Motion-aware tracking presets

The preset tracking options include motion detection:

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Responsive preset

Includes motion detection for optimal battery usage: 
let options = RadarTrackingOptions.presetResponsive
// useMotion is automatically configured
// useVisits is enabled
// useSignificantLocationChanges is enabled

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Efficient preset

Uses visit detection which relies on motion sensors: 
let options = RadarTrackingOptions.presetEfficient
// useVisits is enabled (uses motion detection internally)

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Receive motion updates

Receive activity updates through the Radar delegate: 
import RadarSDK

class MyRadarDelegate: NSObject, RadarDelegate {
    func didUpdateLocation(_ location: CLLocation, user: RadarUser) {
        // Check user's current activity
        if let activityType = user.foreground {
            switch activityType {
            case .stationary:
                print("User is stationary")
            case .foot:
                print("User is walking")
            case .car:
                print("User is driving")
            default:
                print("Activity: \(activityType)")
            }
        }
    }
}

// Set the delegate
Radar.setDelegate(MyRadarDelegate())

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Implementation details

The SDK manages motion detection through the RadarActivityManager class which:
  1. Initializes motion activity monitoring when useMotion is enabled
  2. Starts activity updates from CoreMotion’s CMMotionActivityManager
  3. Monitors relative altitude using CMAltimeter when usePressure is enabled
  4. On iOS 15+, also monitors absolute altitude using CMAbsoluteAltitudeData
  5. Automatically stops updates when tracking is stopped
The RadarSDKMotion framework must be integrated for motion features to work. If the framework is not present, the SDK will log a warning and motion features will be disabled.

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Best practices

Request permission early

Request Motion & Fitness permission when your app launches or during onboarding to ensure smooth tracking.

Combine with geofencing

Use motion detection with useStoppedGeofence to maximize battery efficiency.

Test different activities

Test your app’s behavior while walking, driving, and stationary to ensure proper detection.

Handle permission denial

Gracefully handle cases where users deny Motion & Fitness permission.

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Troubleshooting

  • Verify the RadarSDKMotion framework is integrated
  • Check that Motion & Fitness permissions are granted
  • Ensure useMotion is set to true in tracking options
  • Check logs for “RadarSDKMotion detected and initialized” message
  • Verify the device has a barometer (iPhone 6 and later)
  • Ensure Motion & Fitness permissions are granted
  • Set both useMotion and usePressure to true
Adjust the stopDuration and stopDistance parameters:
  • Increase stopDuration for less sensitive detection
  • Decrease stopDistance for more precise stop detection
  • Typical values: 140 seconds and 70 meters